VxWorks5.5之usrInit函数分析（usrConfig.c）

因为使用的镜像是VxWorks_rom，所以usrInit函数在文件config/all/usrConfig.c中定义，由romStart函数调用，此时中断为全关状态，多任务内核还未开启，主要完成清除BSS段，设置中断向量表，初始化硬件最后使用usrRoot启动内核。

下面是以S3C2410为例，将源码中不必要的部分去除后的代码：

#define TRAP_VALUE_1	0x12348765
#define TRAP_VALUE_2	0x5a5ac3c3
LOCAL volatile UINT32	trapValue1	= TRAP_VALUE_1;
LOCAL volatile UINT32	trapValue2	= TRAP_VALUE_2;
void usrInit
(
int startType
)
{
while (trapValue1 != TRAP_VALUE_1 || trapValue2 != TRAP_VALUE_2)//用以检查代码段复制是否成功完成，成功完成的含义如是否对齐到合适的内存位置，以及在复制过程中数据是否完好等
{
/* infinite loop */;
}
#ifdef INCLUDE_SYS_HW_INIT_0
SYS_HW_INIT_0 ();//sysHwInit0(),在文件sysLib.c中定义
#endif /* INCLUDE_SYS_HW_INIT_0 */

/* configure data and instruction cache if available and leave disabled */

#ifdef  INCLUDE_CACHE_SUPPORT
cacheLibInit (USER_I_CACHE_MODE, USER_D_CACHE_MODE);//设置指令和数据Cache的模式
#endif  /* INCLUDE_CACHE_SUPPORT */

bzero (edata, end - edata);		/* zero out bss variables */

sysStartType = startType;			/* save type of system start */

intVecBaseSet ((FUNCPTR *) VEC_BASE_ADRS);	/* set vector base table */

excVecInit ();				/* install exception vectors 安装中断处理程序*/

sysHwInit ();				/* initialize system hardware */

usrKernelInit ();				/* configure the Wind kernel */

#ifdef INCLUDE_USB
#   ifdef INCLUDE_OHCI_PCI_INIT
sysUsbPciOhciInit ();
#   endif
#endif
cacheEnable (INSTRUCTION_CACHE);		/* enable instruction cache */
cacheEnable (DATA_CACHE);			/* enable data cache */
/* start the kernel specifying usrRoot as the root task */

kernelInit ((FUNCPTR) usrRoot, ROOT_STACK_SIZE,
(char *) MEM_POOL_START_ADRS,
sysMemTop (), ISR_STACK_SIZE, INT_LOCK_LEVEL);
}

在usrInit函数中调用了一些其他的函数，例如sysHwInit0()（在sysLib.c中定义），同样去除无关的代码后，如下：

void sysHwInit0 (void)
{

#ifdef INCLUDE_CACHE_SUPPORT
/*
* Install the appropriate cache library, no address translation
* routines are required for this BSP, as the default memory map has
* virtual and physical addresses the same.
*/
cacheArm920tLibInstall (NULL, NULL);//cache Lib
#endif /* INCLUDE_CACHE_SUPPORT */

#if defined(INCLUDE_MMU)
/* Install the appropriate MMU library and translation routines */
mmuArm920tLibInstall (NULL, NULL);//MMU Lib
#endif
return;
}

可以看出该函数主要负责CACHE和MMU单元的支持

接着调用函数intVecBaseSet和excVecInit完成中断初始化，紧接着调用sysHwInit完成板级硬件的初始化，具体如下：

void sysHwInit (void)
{
/* install the IRQ/SVC interrupt stack splitting routine */
FAST PART_ID  partId;

_func_armIntStackSplit = sysIntStackSplit;

#ifdef INCLUDE_SERIAL
/* initialise the serial devices */
sysSerialHwInit ();      /* initialise serial data structure */
#endif /* INCLUDE_SERIAL */
}

该函数主要调用sysSerialHwInit函数完成串口的初始化.

sysHwInit函数执行完后，接着执行usrKernelInit完成内核数据结构的配置，同样去除无关代码后，如下：

/*******************************************************************************
*
* usrKernelInit - configure kernel data structures
*
* NOMANUAL
*/
void usrKernelInit (void)

{

classLibInit ();			/* initialize class (must be first) */
taskLibInit ();			/* initialize task object */

#ifdef	INCLUDE_TASK_HOOKS //在Makefile中已定义
taskHookInit ();			/* initialize task hook package */
#ifdef	INCLUDE_SHOW_ROUTINES//在Config.h中定义
taskHookShowInit ();		/* task hook show routine */
#endif	/* INCLUDE_SHOW_ROUTINES */
#endif	/* INCLUDE_TASK_HOOKS */

#ifdef	INCLUDE_SEM_BINARY//在Makefile中定义
semBLibInit ();			/* initialize binary semaphore */
#endif	/* INCLUDE_SEM_BINARY */

#ifdef	INCLUDE_SEM_MUTEX//在Makefile中定义
semMLibInit ();			/* initialize mutex semaphore */
#endif	/* INCLUDE_SEM_MUTEX */

#ifdef	INCLUDE_SEM_COUNTING//在Makefile中定义
semCLibInit ();			/* initialize counting semaphore */
#endif	/* INCLUDE_SEM_COUNTING */

#ifdef        INCLUDE_VXEVENTS//在Makefile中定义
eventLibInit ();
#endif        /* INCLUDE_VXEVENTS */

#ifdef	INCLUDE_WATCHDOGS//在Makefile中定义
wdLibInit ();			/* initialize watchdog */
#ifdef	INCLUDE_SHOW_ROUTINES//在Makefile中定义
wdShowInit ();			/* watchdog object show routine */
#endif	/* INCLUDE_SHOW_ROUTINES */
#endif	/* INCLUDE_WATCHDOGS */

#ifdef	INCLUDE_MSG_Q//在Makefile中定义
msgQLibInit ();			/* initialize message queues */
#ifdef	INCLUDE_SHOW_ROUTINES
msgQShowInit ();			/* message queue object show routine */
#endif	/* INCLUDE_SHOW_ROUTINES */
#endif	/* INCLUDE_MSG_Q */

#ifdef	INCLUDE_SHOW_ROUTINES//在Makefile中定义
classShowInit ();			/* class object show routine */
taskShowInit ();			/* task object show routine */
semShowInit ();			/* semaphore object show routine */
#endif	/* INCLUDE_SHOW_ROUTINES */

/* configure the kernel queues */

#ifdef	INCLUDE_CONSTANT_RDY_Q//定义了
qInit (&readyQHead, Q_PRI_BMAP, (int)&readyQBMap, 256); /* fixed ready q */
#else
qInit (&readyQHead, Q_PRI_LIST);	/* simple priority ready q */
#endif	/* !INCLUDE_CONSTANT_RDY_Q */

qInit (&activeQHead, Q_FIFO); 	/* FIFO queue for active q */
qInit (&tickQHead, Q_PRI_LIST); 	/* simple priority semaphore q*/

workQInit ();			/* queue for deferred work */
}

#endif /* __INCusrKernelc */

紧接着，启用指令和数据Cache功能，并讲usrRoot作为根任务启动内核.